How much fertilizer do I have to add to my plants?

Today, in Gardenprue , a fairly technical article awaits us, where we are going to know the exact needs that a soil has regardless of the plant we grow (that will depend on the maintenance subscriber). Imagine that we have a soil that we have never fertilized. How do we prepare it? Let’s get to know it.

Basically, what we are talking about is the bottom fertilizer or the way in which we previously prepare the soil, but it also serves to improve the conditions of our garden. Imagine that you have to prepare a deep bed . We are putting the same amount of organic compost (compost or manure) in poor soil as in rich soil, and in principle it should not be like that. Well, since you are not picky, total, for a small garden you should not go around fooling around, right?

But what if we do it on a large scale or have a large orchard? Here already, every kilogram of fertilizer counts and we can greatly optimize it with a few simple formulas. Do we try?

FIRST OF ALL, KNOW WHAT OUR SOIL IS LIKE

To do it well we need to know a series of parameters. One of them is to know what texture our soil has. We can do it through a soil analysis or in a homemade way as we already discussed.

From this we can already have great information on our soil, and we will know the drainage, the way in which we have to irrigate and, also very important, the quality of the water (whenever we can choose).

THE IMPORTANCE OF THE BACKGROUND SUBSCRIBER

The bottom fertilizer is an amendment that we make 1 or 2 months before planting any crop. What we seek is to increase the properties of our soil, improve texture, drainage, and ultimately, make a much more pleasant bed for our plants. Knowing how much to add is simple.

Imagine that we know ( through a soil analysis ) that our plot where we want to cultivate has 1.6% organic matter. It is a fairly low percentage where periodically we will have to pay our plants in depth.

Some prestigious authors  establish between 2 and 3% of organic matter as optimal for a soil. There are those who ask for more, but we, who have a saving mentality, consider that 2% is more than enough to maintain our garden. If you have economic pretensions, maybe you can go up a little more. 😉

Well … let’s start with the calculations …

PREVIOUS DATA:

  • Soil density: 1.74 gr / cm3
  • Percentage of organic matter in our soil: 1.6
  • Soil enhancement depth: 0.3m

HOW MUCH ORGANIC MATTER DOES OUR SOIL CURRENTLY HAVE?

Amount of MO [2%]: 10,000 (m2) · 0.3 (m) · 1.74 (gr / cm3) · (2/100) = 104,400 [kg / ha] = 104.4 [t MO / ha ]

But we have 500 square meters of garden, so it would have to be 5,220 kg.

It’s a lot of organic matter, and it’s what we want! Now let’s see how much our soil currently has …

Amount of MO [1.6%]: 10,000 (m2) · 0.3 (m) · 1.74 (gr / cm3) · (1.6 / 100) = 83.520 [kg / ha] = 83.52 [ t MO / ha]

And for the surface of our garden: 4,176 kg

Now we will simply have to subtract the ideal amount with ours:

Amount of MO we need: 5,220 – 4,176 = 1,044 kg

Look, to vastly improve our soil we only need 1,044 kg (just over a ton) of organic matter.

OK … AND HOW MUCH DOES THAT COST?

As always, we have to see if it is economically feasible to provide this amount of organic matter. To do this, we go to the gardening price bases and see what 1 cubic meter costs (later we will convert it to kg) of  treated manure. 

1 cubic meter of treated manure = € 27.29

Looks cheap doesn’t it? Well, after all, they are animal waste … 😉

HOW MANY KG DOES A CUBIC METER HAVE?

To know this we need to know the density of the manure. There are two authors (Boussignault, Keyser) who agree that the mean density of manure is 400-500 kg / cubic meter. We, who are looking for the middle ground, are going to leave it at 450 kg. Now we know that 450 kg of treated manure is worth € 27.29.

As we needed 1,044 kg, this amount of treated manure will cost us € 63.

Only € 63 separates you from a great improvement of your floor!

This has been a clear example that you can easily adapt to your working conditions. The only difficult thing to do is to know the current percentage of organic matter in your soil. Knowing the rest is easy. Just the soil surface, the depth to which you would like to improve it and the density, and voila!

If you want, you can start to generate this amount completely at home. 

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